Alten is a holding company. Through its subsidiaries, Co. operates in three areas: Engineering and Technology Consulting (ETC), Telecoms Networks and Multimedia, and Information Systems (NTIS). Through the Engineering and Technology Consulting (ETC) segment, Co. studies and designs technology products for technical divisions in industry and telecoms. The Telecoms Networks and Multimedia segment focuses on Product design, Architecture, deployment, and operation of networks. Lastly, the IT systems segment comprises Applications and software development, and Infrastructure and Telecoms (Applications, systems and networks Corporate telecommunications).

Clasquin Group designs and supervises the entire overseas transport & logistics chain. Co. has two operating segments: air and sea freight forwarding and related services ("overseas freight") and IT service contractor ("IT services"). The air freight forwarding and related services ("overseas freight") segment comprises of three business lines: air freight forwarding and related services, sea freight forwarding and related services, other services not included in air and sea freight (including related services) are grouped into the "others" business line.

Groupe Gorge is a holding company engaged in three areas of operation: Smart Safety Systems (develops Smart Safety Systems designed to operate in hostile and constrained environments for civil and defense sectors); Protection in Nuclear Environments (protection solutions in nuclear environments: shielding by partition systems in nuclear power stations & protection against radiation for staff working in nuclear environments); and Industrial Project Services (industrial projects and maintenance, creating production tools and turnkey operation areas, projects and services in industrial robotics, iron works, automation, 3D printer offerings, electricity and fire fighting systems).